Assemb ly for the control of electrical units



June 14, 1960 s. N. ZARRILLO 2,941,175

ASSEMBLY FOR THE CONTROL OF ELECTRICAL UNITS Filed July 24, 1958 3 Sheets-Sheet 1 I NVEN TOR.

/5 M QJULMJE Mr/ 7% June 14, 1960 s. N. ZARRILLO 2,941,175

ASSEMBLY FOR THE CONTROL OF ELECTRICAL UNITS Filed July 24, 1958 3 Sheets-Sheet 2 BY )Q g Mdkmc 477'02/VEYS June 14, 1960 s. N. ZARRILLO 2,941,175

ASSEMBLY FOR THE CONTROL OF ELECTRICAL UNITS Filed July 24, 1958 s Sheets-Sheet s k k Q :1

INVENTOR.

ITTP/VEYS United States Patent Salmon Falls, N.H., assignor to Co., Inc., Dover, N-.H;, a corporation This invention relates to a structurally and functiona1- ly' improved assembly for the control of electrical units.

By -means of-the present teachings a structure is provided in which a number of units may be independently controlled or adjusted, or atthe option of the operator, may be controlled or adjusted together and caused to function in unison through the operation of but a single governing unit.

Another object is" that of furnishing a structure of this type which will involve relatively few parts, each individually simple and rugged in construction, and such parts being capable of readyassembly to provide a unitary structure-operating over long periods of time with freedorn from all difficulties. I

With these and other objects in mind, reference is-had to the attached sheets of drawings illustrating practical embodiments of: the invention and in which:

Fig. 1 is a side elevation of a control assembly and units associated therewith;

Fig. 2 isafrontview thereof;

Fig. 3-is a transversesectional view in enlarged scale; taken 'along the line 3-3 in the direction of the arrows asindicated 1in:Fig. 2;

Fig. 4 is-a sectional plan view of the assembly and unit as shown in Fig. 3 and-takenalong the line 4-4- in the direction of-the arrows as indicated inthelatter figure;

Fig. 51is a fragmentary sectional view showing the parts in a position different. from that illustrated in Figs. 3 and 4;

Fig; 6".is azface view ofthe innermost control unit of the assembly; a

Fig. 7 is. an. exploded perspective view ofthe clutchstructureas embodiedin'the assembly;

Fig; 8 is1a side elevationof an alternative assembly; and

Fig; 9xisv afragmentary. sectionalnview, in enlarged scale, of certain-of the parts shown'in Fig 8.

With a view to,simplifying the illustration, merely apair of units to be. controlledhave been shown; In many: respects thlSrlS a preferred embodiment of the in vention. However, it is to be understood this showing is merelyyillustrative, and the control structure might-- with, slight modification, of the. parts-be applied to' a larger number; ofelectrical units the operations :of which are. to;be, governed;

Thus, referring.v primarily to the assembly. as shown in Figs l to 7'inclusive, thenurnerals .10 and lltindi cate the casings of electrical circuit-controlling units. These may embrace'potentiometers, variable resistances or other desired assemblies. The casings are preferably cup-shaped and have extending from their free edges, tabs Hand 13. The former serve to retain parts .in applied positions with respect to agiven casing. The latter function as guiding and positioning elementsbetween thecasings. Conveniently, the plate 14.0f the rearmost casing 10, which is retained by lugs 12, h-as'extending from itsforward face hook-shaped elements 14'. 4

2,941,175 Patented June 14, 1960 These enter slots formed in the adjacent base of casing 11 to retain the parts in position, as taught, for example,v

in prior United States. patent to Mucher No. 2,814,702 of November 26, 1957.

Preferably extending beyond the side faces of the casings 10 and 11 and through gaps in the latter are dielectric panels or plates 15. These serve to mount terminals 16, 17 and 18 connectible with leads extending from circuits to be controlled. In order to support the assembly upon a mounting; the forward control unit 11 has its open face-closed by a plate 19 generallycorresponding to plate 14, but mounting a bushing or boss 20. A mounting panel (not shown) beingprovided with an opening of a diameter adequate to permit of the passage of the boss,

it is. obvious that the assembly may be: disposed adjacent Extending forwardly of the bushing 20 are a pair'of.

shafts 21 and22; The latter is hollow and receives with in. its bore the; rear portion of: shaft 21; that shaft ex tending both forwardly and. rearwardly of the shaft 2 2. I To retain shaftlziagainstaxial movement, although per 2 mitting of free. rotation. of' the. same, the: face of.'*thatshaft is formed with grooves adjacentthe forward and rear surface'sof the. bushing or boss.20. Each: of' these grooves. receives a retaining ring of, for example; the- G-type retainingring.designated by the numeral. 23111 the figures and seen clearly in Fig. 3, which bears against the. adjacent faceof. the:- bushing. Shaft 22 extends within;

Shaft 21 extends casing 11. and terminates therein. through. that; casing; into the casing 10. Bothsliafts 21' and'22 canrotate withxrespect tocasings 10:and 1 1- and each. other. Also, shaft 21 can be shifted axially of shaft 22 and during such shifting be slidably supported" by the bore face of the latter which is not axially shift-. able.-

In the illustratedembodiment the electrical control" units have-ibeen shown as Potentiometers. Assuchptheir panels 15? support upon their inner faces variable" resistances 24"ofany wellknown suitable type. Thebodies.

ofthese resistances. are. concentrically disposedwith re.-

Spectatotheaxis of. the entireassembly. These resistance paths furnishthe stators of thefunit. Rotors are provided'. by preferably employing a plate 25. of insulating material within casing 11: and a plate 26- of. slightly different configuration as shown in the figures-within casing 10. Mounted upon each of these'plates is-acontact spring assembly including a disk whichhas its edge 27 folded aroundrtheextended portion of its respective."

plate25- or 26,1and from which extendia'pair of contact springs; 28 to engage the surface of the respective: re-

sistance 24. The opposite ends of the resistance 24 are preferably connected one to each. of" terminals- 16 and 18. The'cent-ralterminal member 17 may be extended,

asat29, to'furnisha resilient contact member Iyieldinglybearing against the surface of the contact springassembly plate associated therewith.

One or both 20f the. rotors may have associated with it a .stop. structure, as is usual in assemblies of this nature. Conveniently, that'structure'embraces a plate 30 fixedly securedtoshaft-22 and presenting an angular. end por tion*31.' Thelatter'will cooperate with a fixed projecting portion(notshown) to limit th'eturning of ihBzIOtOI.

The contact springs 28 within casing 11 will'together with spring 29.--assure that the rotor is maintained proper n 1y spaced with respect to its resistance 24; incident tothe i yielding pressure exerted. Similarly, rotor 26 within casing is maintained in proper position; that rotor conveniently having an annular flange or base portion 32 which rides in contact with the base of casing 10. Rotor plate 25 will not turn with respect to shaft 22 nor-will it shift axially of the same. Rotor plate 26 will also not turn with respect to shaft 21. However, it will permit that shaft to be shifted axially.

To achieve this result the rear end of shaft 21 is preferably flattened, as indicated at 33 in Fig. 7. Likewise, as shown especially in Fig. 6, the rotor 26 is provided with a. bore 34 which has a configuration corresponding to flattened portion 33. Therefore, flattened portion 33 of the shaft maybe received within that bore, and the length of the flattened portion is such that within the limits of axial movement of shaft 21, disengagement will not occur between the end portion 33 thereof and the surface of bore 34. Accordingly, no relative turning of these parts will be possible. However, relative axial movements thereof can occur. Incident to such movements, a clutching or interengagement of the elements results such that they may either be rotated independently of each other or be turned in unison.

Shaft 21, at a point short of its flattened end, is provided with a groove or reduced section 35. The wall of the groove toward the outer end of that shaft is preferably contoured as at 36 to furnish a camming portion. A spring clutch is furnished by providing a pair of opposed resilient arms 37 extending inwardly toward each other and preferably terminating in outwardly flared lips 38, as in Fig. 7. The inward zones of the arms, as at 39, furnish engaging portions. Under the normal resiliency of these arms, those engaging portions are spaced a distance less than the maximum diameter of shaft 21. However, they are spaced a greater distance than the diameter of the base of groove 35. These arms are conveniently integral with each other and extend from a mounting ring 40 conveniently formed with notches 41 in its inner edge. As illustrated particularly in Fig. 4, extended portions 42 of shaft 22 project through the notches 41 in order to prevent the spring from rotating with respect to that shaft. Also, in this manner the spring is retained against any axial movements with respect to the rotor assembly within casing 11. Therefore, when shaft 21 is moved to the right, as in Fig. I, contact portions 39 will ride within and clear the base of groove 35. However, when shaft 21 is shifted to the left, then contact portions 39 will override the cam surface 36 to force the spring arms away from each other and so into contact with the surface of shaft 21. Accordingly, those fingers will serve as a clutch, so that as shaft 21 is rotated, they will move in unison with it. Being connected to the rotor plate 25,'they will accordingly rotate that plate. Therefore, the rotors of both units 10 and 11 will turn in unison.

Briefly surveying the operation of the assembly, and with the parts in the positions shown in Figs. 3 and 4, it is apparent that actuating members (not shown) attached to shafts 21 and 22 will serve to turn those shafts independently of each other. When the electrical values have once been properly established insofar as units connected to casings 10 and 11 are concerned, then the operator may shift shaft 21 from the position shown in Figs. 3 and 4 to that illustrated in Fig. 5. So shifted, an operation of either of the shafts to rotate the same will result in a unified rotation of the assemblies within both casings. Accordingly, it is apparent that in an installation involving two amplifier channels, the controls are initially operated individually to establish a desired balance. Thereupon, with the two controls or sections locked together, simultaneous operation occurs, while the balanced condition is maintained. unit assembly, the volume of each amplifier may be precisely controlled and established. Thereupon, the over-all volume may be increased or decreased to furnish In the case of a two- V a combined bass and treble control capable of individual adjustment.

Now, referring to the structure shown in Figs. 8 and 9, it will be seen that in many respects the assembly is identical with that heretofore described. However, the circuit-controlling units have been spaced a substantial distance from each other. Thus, the numeral 43 indicates the unit corresponding to unit 11 in the earlier figures. This units is supported upon a panel 44. A

second panel or supporting structure 45 is provided to the rear of and spaced from unit 43. Upon this second mounting a unit 46 is disposed corresponding. to. the earlier unit 10-. Both of the units are furnished with bushings or boss portions conveniently projecting through openings in the mountings and receiving nuts (not shown) to maintain them axially in alignment with each other.

The interior or contained mechanism of units 43 and 46 may correspond identically with the parts as heretofore described. The rotor of unit 43 is controlled by a hollow shaft 48. The latter mounts a suitable actuating element, such as a knob (not shown). Conveniently extending from the rear end of shaft 48 is a clutch spring 50 corresponding to spring 37. A relatively long shaft 49 ex-- tends slidably through the bore of shaft 48 and is provided with a groove 51 within which the ends of spring 50 may lie when the parts are in one position. Otherwise, the spring ends will bear against the large diameter face of shaft 49, as shown in Fig. 8. The length of the shaft is such that it bridges the space between panels 44 and 45 and extends into unit 46. Within that ,zone it is provided with a non-circular portion 52 corresponding to part 33 of shaft 21. The rotor 53 of unit 46 is-furnished with a socket or bore contoured to correspond 'to the rear end portion 52 of shaft 49. Therefore, this shaft is slidably but non-rotatably received within the rotor.

As will be understood, an assembly of the type shown in Figs. 8 and 9 may have one of its components, such as 43, initially installed as part of an apparatus. That component, when properly connected, will function in an entirely satisfactory manner by simply turning shaft 48. Subsequently, and in a more complex assembly, unit 46 may be installed. That unit will include shaft 49. In such installation, unit 46 will be properly vdisposed with respect to its mounting 45. Shaft 49 will be introduced through the bore of shaft 48 and will have its rear portion received within the socket or bore of'rotor 53.

A second control, such as, for example, a knob, will be mounted on the outer end of shaft 49. When that shaft occupies the position shown in full lines in Fig. 8, spring clutch 50 coupled to shaft 48 will bear against the surface of shaft 49, so that a turning of either one of the shafts will result in a simultaneous rotation of both of the control elements of units 43 and 46. When shaft 48 is shifted to the position shown in dotted lines,-then the ends of spring arms 50 will lie within the area of groove 51. In that position, a turning of shaft 48 will have no effect on shaft 49. Likewise, when the latter is turned, by means of a knob or similar actuating element, it will not affect the position of shaft 49. The two shafts may therefore be rotated independently of each other to similarly control units 43 and 46. However, by simply axially shifting shaft 49, these units will be coupled for synchronous movement. As will be apparent, the ends of the clutch spring bearing against the rear surface defining groove 51 will prevent a withdrawal of that shaft beyond a proper position.

Thus, among others, the objects of the invention as specifically aforenoted are achieved. Obviously, numerous changes in construction and rearrangements of the parts may be resorted to without departing from the spirit of the invention as defined by the claims.

I claim:

disposed in substantially axial alignment, a pair of control shafts, one of said shafts being hollow and concen trically disposed with respect to the other and the latter shaft being slidably supported by said hollow shaft, said latter shaft extending through the control unit to which said hollow shaft is connected, said shafts being connected each to a rotor to turn the same independently of each other, means whereby said latter shaft is movable axially within said hollow shaft from a first to a second position and means preventing relative rotation of said shafts when said latter shaft is in its second position.

2. An assembly in accordance with claim 1, in which the connection between the inner shaft and its associated rotor consists of a non-circular portion of said inner shaft and the rotor being formed with a correspondingly contoured bore slidably receiving such non-circular portion.

3. An assembly in accordance with claim 1, in which the means preventing relative rotation of the shafts in the second position of the latter shaft comprises a resilient finger connected to one of said rotors and yieldingly bearing against a surface of the inner shaft.

4. An assembly in accordance with claim 3, in which the inner shaft is formed with a groove and the resilient finger is attached to the rotor associated with the outer shaft and constructed and arranged so that the finger is disposed within said groove upon relative movements of said shaft when the latter shaft is in its first position.

5. A control unit for use in an electrical circuit assembly comprising in combination a bushing, a hollow circular shaft journaled within said bushing, a second circular shaft within the hollow of said hollow circular shaft concentric with the hollow shaft and formed to rotate independently of said hollow shaft and undergo limited relative axial movements thereof, a rotor rigidly connected with said first shaft, a second rotor, a resilient spring attached at one end to said rotor, an engaging portion of said spring, a flattened end portion of said second shaft, a bore portion *of said second rotor having a configuration corresponding to said flattened end portion and receiving said flattened end portion, the axial length of said flattened end portion being such that within the limits of axial movement of said second shaft disengagement would not occur between said flattened end portion and the bore portion, a groove in said second shaft, a first axial position of said second shaft, a second axial position of said second shaft, said engaging portion of said spring embracing the periphery of said second shaft in its first axial position and being disposed within said groove When said second shaft is in its second axial position and a cam surface of said groove whereby said engaging portion slides when said second shaft is moved from one of said positions to the other.

ReferencesCited in the file of this patent UNITED STATES PATENTS 1,871,876 Brehany Aug. 16, 1932 2,650,270 Mucher Aug. 25, 1953 2,868,967 Poppa et a1. Jan. 13, 1959 

